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Cfjc UniUersfitp of Cfjicaso 



CHANGES IN FOOD VALUE OF VEGETABLES DUE TO 

COOKING 



A DISSERTATION 

SUBMITTED TO THE FACULTY 

OF THE GRADUATE SCHOOL OF ARTS AND LITERATURE 

IN CANDIDACY FOR THE DEGREE OF 

DOCTOR OF PHILOSOPHY 

DEPARTMENT OF HOUSEHOLD ADMINISTRATION 



BY 

MINNA CAROLINE DENTON 



Private Edition, Distributed By 

THE UNIVERSITY OF CHICAGO LIBRARIES 
CHICAGO, ILLINOIS 



Reprinted from 

Journal of Home Economics, Vol. XI, No. 4 

April, 1919 



•«(■ 






®fje ^anibergttp of Chicago 



CHANGES IN FOOD VALUE OF VEGETABLES DUE TO 

COOKING 



A DISSERTATION 

SUBMITTED TO THE FACULTY 

OF THE GRADUATE SCHOOL OF ARTS AND LITERATURE 

m CANDIDACy FOR THE DEGREE OF 

DOCTOR OF PHILOSOPHY 

DEPARTMENT OF HOUSEHOLD ADMINISTRATION 



BV 

MINNA CAROLINE DENTON 



Private Edition, Distributed By 

THE UNIVERSITY OF CHICAGO LIBRARIES 
CHICAGO, rLLTNOIS 



Reprinted from 

Journal of Home Economics, Vol. XI, No. 4 

April, 1919 






MAY 2Q I9» 



Reprinted from Thb Journal of Home Economics, Vol. XI, No. 4, April, 1919 



CHANGES IN FOOD VALUE OF VEGETABLES DUE TO 

COOKING* 

Effect of Varying Household Manipulations 

minna c. denton 

i. introduction 

Recent progress in nutrition is emphasizing heavily the inadequacies 
of a diet with a preponderance of cereal products and vegetable fats — our 
cheapest sources of protein and calories — at the same time that food 
scarcity puts some of their most effective supplements, such as eggs, 
milk, meat, and animal fats, very nearly out of the reach of all except 
the well-to-do classes. It seems that many of the fresh vegetables and 
fruits have some value, in several respects, as supplements to inadequate 
diets of certain types. But at most seasons of the year these, too, are 
considered to be out of reach of the limited purse, with a few exceptions, 
prominent among which are vegetables which may be canned in time of 
plenty, and the "winter vegetables." If these local products are to be 
more largely used in the diet, both as supplements to the cereals and meats 
and as substitutes for them, an extended knowledge of their value with 
regard to various dietary factors is desirable. This study is concerned 
with the factors which are usually the first ones to be determined — their 
fuel values and ash content^ — these being determined from the vegetables 
as served to us at the table, after household manipulation, possibly also 
after commercial manipulation, as in the case of canned foods. 

With the exception of potatoes, the winter vegetables are mostly 
strong-juiced or highly flavored, and their flavors do not commend 
themselves to all persons, particularly often not to those of highly dis- 
criminating or of irritable nervous organizations, unless the flavor can 
be somewhat modified. Partly for this reason and partly for purposes 
of convenience, the methods very generally employed in cooking and in 
canning them have involved the use of a greater or less excess of water, 
which has considerable extractive power at the temperatures employed. 

* This paper was presented as part fulfillment of the requirements for the degree of Ph.D. 
in Household Administration, University of Chicago, August, 1918. 

1 



2 THE JOURNAL OF HOME ECONOMICS [April 

Food conservationists are urging that these vegetable foods should be 
baked, or steamed, or boiled in their jackets, or that the vegetable stock 
should be utilized; yet practical objections, such as those in the following 
list, continue to be urged upon some occasions. 

1. It is apparent that neither cabbage heads nor large root stalks can 
be boiled whole, — ^their size forbidding this possibility. 

2. Chlorophyl-bearing tissue usually turns more or less brown when 
steamed, though boiling water (even distilled, but especially when" hard" 
or when salted or made alkaline with soda) satisfactorily "sets" the 
green color of cabbage, cauliflower, Brussels sprouts, peas, string beans, 
and the yellow color of blanched celery. If the cooking be not too long 
continued, this green color is satisfactorily retained in boiled vegetables. 

3. The steamed product is dryer and less water-logged than the boiled, 
and of different texture; it has of course no flavor of added salt, and yet 
(steamed at 90° to 100°C.) it may retain its characteristic odor and taste 
more strongly than does the boiled vegetable. The consequence is 
that the uninitiated frequently pronounce steamed cabbage both rank 
and insipid, also "not done." 

4. The washing of spinach or greens which have been transported for 
long distances "packed in mud" (cracked ice) is a tedious process and 
often more or less of a failure, even when a good deal of pains has been 
taken. Under these circumstances it is a great help to boil in excess of 
water and skim out the greens when done, because thus the remaining 
sand and grit fall to the bottom of the kettle, instead of sticking to the 
leaves, as is the case with the steamed product. 

5. The strong taste of condensed spinach juice, such as is produced by 
cooking the leaves in a very small amount of water, proves objectionable 
to many persons, including children not old enough to express them- 
selves verbally upon the subject. 

6. Baking is desirable, yet often impracticable for various reasons, 
among which are the expense of fuel, and the overheating of the kitchen 
from the oven. 

7. Home and commercial canning methods alike usually call for a pre- 
liminary "blanching" process which is advisable for various reasons; yet 
this period of boiling in excess of water, which apparently is never utilized 
to advantage, seems inconsistent with our customary efforts to "save 
the juice." (This objection does not apply to the steam blanch or to 
blanching in skins.) 



1919] CHANGES IN FOOD VALUE OF VEGETABLES 3 

8. The vegetable canned in excess of water at high temperature, as 
arc some of the commercially prepared products, may well lose a large 
part of its nutrient values of various sorts to the "juice" drained off 
when the can is opened; yet this juice, especially when excessive in 
amount, is often not palatable, and is feared by some because of its pos- 
sible content in tin, lead, or iron salts derived from a metal container, 

9. The cook often finds it a convenience to pare vegetables and cut 
them ready for serving, early in her preparation of the meal. She does 
not wish to add peeling of potatoes or carrots to the list of things which 
must be done in the busy period just before the meal is served when the 
biscuits are to be baked and the coffee to be put over, the gravy to be 
made, and the salad to be dressed. She therefore objects to cooking 
vegetables in their skins. 

10. The use of a large rather than a small amount of water with vege- 
tables shortens the period of their cooking to such an extent that the 
average home cook often prefers to use an excess of water rather than 
barely water to cover. 

Thus it would appear that a single generalization does not suffice to 
dispose of all cases, but that the cooking of each vegetable is a question 
to be decided on its own merits, if the conservation of nutritive value is 
to be combined with maximum palatability and practical convenience. 

Other questions which occur to the dietitian who compares the cooked 
vegetable with the raw, are such as these: After careful consideration of 
the details of every-day practice to be observed all about us, how are 
we to estimate the dietetic value of vegetables cooked in diverse ways? 
Shall we in computing or planning dietaries, assign to the cooked vege- 
table 90 per cent or 75 per cent or 50 per cent of the caloric value of the 
edible portion of raw vegetables? What is the proportionate loss sus- 
tained by vegetables which have been "blanched" in excess of unsalted 
boiling water, as practiced in some canning processes; by vegetables 
covered with water and cooked in quart jars in batli of boiling water for 
two and three hours, as recommended for home canning? Does the vege- 
table with high content of soluble carbohydrate lose proportionately 
more than that with lower content? Does the root stalk cut into large 
pieces suffer considerable loss? Do uncut vegetables which present a 
large amount of exposed cuticle (leguminous seeds, leaf greens, fleshy 
buds and flowerets as loose-leaved cabbage and cauliflower) suffer con- 
siderable loss from the extractive effect of boihng water? Are the losses 
from steaming at 90° to 100°C. (efficient home steamer) negligible; are 



4 THE JOURNAL OF HOME ECONOMICS [April 

those from direct exposure to steam at 100° to 120°C. (institutional 
cooker) also negligible? Does the addition of salt to the cooking 
water, in small amounts (1.5 per cent solution at beginning of process) 
increase or diminish the cooking loss? Does the loss diminish if section- 
ing be done longitudinally (parallel with the fibro-vascular bundles) 
rather than crosswise (across them, exposing their cut ends at both 
surfaces of each slice to the solvent action of water)? 

II. REVIEW OF LITERATURE ON LOSSES IN COOKING VEGETABLES 

Most of the work done on losses of cooked vegetables is concerned 
chiefly with mineral constituents. In many cases very few details as to 
method of cooking are given, which makes it difficult to compare results 
of different investigators. 

Wagner and Schaefer^ reported finding that potatoes steamed in their 
skins lost 1.17 per cent of their crude ash, 0.69 per cent of their potas- 
sium, 0.03 per cent of their phosphorus. Steamed after paring, these 
losses were 7.28 per cent, 6.93 per cent, and 4.57 per cent, respectively. 
Boiled in their skins, they lost 3.64 per cent of their crude ash, 3.32 
per cent of their potassium, 1.12 per cent of their phosphorus; boiled 
after peeling, 28.86 per cent, 38.33 per cent, and 22.87 per cent, re- 
spectively. 1 kgm. of spinach lost 8.578 grams of dry matter (1.684 
gram N, 3.375 grams of ash); 1 kgm. of carrot tops, chopped, lost 15.252 
grams dry matter (3.312 grams N, 6.331 grams ash). Average losses in 
boihng were 9 to 18 per cent of the total soluble matter found in the 
unboiled vegetable food. 

Snyder, Frisby, and Bryan t^ found that potatoes when pared, soaked 
3 to 5 hours, and put over to cook in cold distilled water, lost 46 to 58 
per cent of their total nitrogen (about one-half of which is in the fomi 
of protein), 25 per cent of their protein, and 38 per cent of their mineral 
salts. When pared, put into either hot or cold distilled water, and 
cooked at once, the losses were half these amounts or less; when cooked 
in skins, the nitrogen loss was 1 per cent, the protein loss 0.5 per cent, the 
mineral loss 3.3 per cent. Frisby and Bryant, in another experiment, 
found that pared potatoes, put into cold distilled water and cooked, 
lost 9.2 per cent of their nitrogen, 2.7 per cent of their carbohydrate, 

1 Sachs, Landw. Ztschr., vol. 33, p. 369, 1885. (Abstr. in Jahresh. f. Agrikidtur. Chem., 
N. F. 8, vol. 28, p. 443, 1885.) 

2 BuU. 43, Office of Exp. Sta., U. S. Dept. Agr., 1897. 



^^19] CHANGES IN FOOD VALUE OF VEGETABLES 5 

and 17.2 per cent of their ash; when cooked in their skins, they lost 1.6 
per cent of their ash. Varying the experiments by using "alkaHne 
water'' or "lime water," instead of distilled, produced no important 
variations in losses— except that it seemed that the lune water (and the 
cold alkaline water) took out a httle more protein than did the dis- 
tilled water controls. Carrots, scraped and cut into pieces, lost from 
20 to 40 per cent of their nitrogen, and from 29 to 47 per cent of their 
ash, according to size of pieces. Half a solid cabbage, put into cold water 
and cooked, lost from 33 to 46 per cent of its nitrogen, 33 to 42 per cent 
of its fat and carbohydrate, 48 to 54 per cent of its ash; put into hot water 
and cooked, the losses were usually (but not always) a httle less. On 
the whole, the alkaline and lime waters had a slightly greater extractive 
action than did the distilled water. 

Kraus^ found that cabbage turnip when cooked had lost 20 per cent 
of its carbohydrate; cauliflower, 33^ per cent; spinach, 71 per cent; 
winter cabbage, 53 per cent. 

Zschokke" worked on losses in "blanching" (boilmg in hot water) of 
carrots (cut in pieces), peas, string beans cooked whole and also cut into 
pieces. In each case, one-half of the vegetable was steamed and the 
other half boiled for 25 to 30 minutes. The losses in total dry matter 
were about five times as much by boiling as by steaming; losses in salts, 
usually only from three to four times as great in boiling as in steammg.' 
He gives no data for raw foods, but, if wc were to judge from American 
analyses for these foods, we should conclude that his losses in protein 
and mineral salts were markedly lower than tliose reported by most 
workers, while his losses in "nitrogen-free extract" run only a httle lower 
than some losses in caloric value reported in the present paper. (He 
found a loss of 3.43 grams of nitrogen-free extract per 100 grams raw ma- 
terial in boiled carrots, 2.43 grams in boiled peas, 0.624 grams in beans 
boiled whole, 0.768 gram in beans boiled in pieces.) 

HaenseP reports a loss of about 0.08 gram of iron oxide from 100 

grams of fresh vegetable, in boiling spinach; and 70 per cent of its 

iron, in boihng lettuce in water— if I have correctly interpreted his report. 

Williams^ gives a number of analyses of cooked foods, calculated to 

moist condition; but in her earlier articles, no corresponding analyses of 

^^Ztschrf.f. Dim. u. physik. Ther., vol. 1, p. 69, 1898. Cited in Hutchison's Food and 
Dietetics. 

* Landu). Jahrb. d. Schwek., vol. 19, p. 615, 1905. 

^ Biochem. Ztschr., vol. 16, p. 9. 

^Jour. Amer. Chem. Sod:',' vol 26, p. 244, 1904. 



6 THE JOURNAL OF HOME ECONOMICS [April 

raw materials were made, so that it is impossible to judge of the propor- 
tionate losses. A later article^ reports a loss of 10.59 per cent of its pro- 
tein and 5.36 per cent of its ash, by celeriac, pared, sHced thin, and 
cooked 30 minutes in boiling water. Chicory, borecole, and endive 
(procedure not stated) lost from 30 to 43 per cent of their protein and 
from 12 to 19 per cent of their ash. Dried legumes (butter beans, green 
flageolets, soy beans), soaked 12 hours and then cooked (whether in the 
same water, and how much, is not stated), lost into their cooking water 
26 to 28 per cent of their protein, and 5.5 to 17.05 per cent of their ash. 
Chestnuts (evidently fresh) lost 54 per cent of their protein and 7 per 
cent of their ash. A still later paper^ evidently reports further work, 
especially with regard to protein losses. Cooked in boiling water by the 
usual method, spinach, with 10 per cent of total solids, loses one-fourth 
of these; celeriac loses half of its total soKds (7 per cent of its ash, 54 
per cent of its protein) ; turnips, almost half; lettuce, one-fourth; aspara- 
gus, one-sixteenth; curly greens (borecole) 40 per cent (16 per cent of 
its ash, 54 per cent of its protein); chicory, 20 per cent (12 per cent of 
its ash, 43 per cent of its protein) ; butter beans, 10 per cent (19 per cent 
of its ash, 30 per cent of its protein); endive, 25 per cent (19 per cent of 
its ash, 30 per cent of its protein). 

Furthermore, Miss Williams gives the following analyses, together 
with those of many other foods, in a table in the Appendix of the third 
volume of Van Noorden's Metabolism and Practical Medicine, 1907. 
It is not stated, whether all of the analyses represent original work, or 
whether some of them are compiled from the works of others. No de- 
tails as to cooking procedure are given. Apparently the analyses for the 
raw vegetables are not intended as strict controls for those upon the 
cooked samples; rather, each represents a sample picked up more or 
less at random. Indeed, the editor's note states that in many cases 
these figures must be looked upon as merely illustrative, rather than as 
the basis for generalizations. It is therefore hardly possible to com- 
pare these results with those given in Tables I and II of this paper. 

These items have been rearranged alphabetically and also so as to 
places figures for raw and cooked samples side by side, instead of having 
them in different tables, as they were printed in the Van Noorden text. 

^ Jour. Indust. Eng. Cheni., vol. 5, p. 653, 1913. 
^ Chem. Neu's, vol. 113, p. 143, 1916. 



1919] 



CHANGES IN FOOD VALUE OF VEGETABLES 



Analyst's of raw and cooked vegetables 



VEGETABLE 



Asparagus 

Artichoke, green 

Artichoke, Jerusalem 

Beans, haricot (dried) 

Beans, scarlet runner 

Beetroot 

Broccoli 

Brussels sprouts 

Cabbage, savoyf 

Carrots 

Cauliflower 

Kale (sea-kale) 

Leeks 

Lentils (dried) 

Onions 

Parsnips 

Peas, (dried) 

Peas, green 

Potatoes, boiled in skins 

Potatoes, boiled after pared . 

Spinach 

Turnips 



PROTEIN 
(NX 6.25) 



Raw Cooked 



per cent 

1.8 

4.8 

2.0 
23.0 

2.3 

1.6 

3.8 

1.5 

1.5 

0.5 

1.8 

1.4 

1.2 
24.2 

1.5 

1.6 
21.0 

7.0 
2.1 
2.1 
2.1 
1.3 



Vegetable marrow 0.6 



per cent 
2.1 

2.9 

1.8 

4.6 

1.8 

0.4 

2.5 

2.8 

0.6 

0.5 

0.9 

0.4 

1.4 

8.8 

0.1 

0.2 

9.4 

2.8 

1.6 

1.6 

0.3 

0.3 

0.1 



Raw Cooked 



per cent 

0.7 
1.6 
1.1 
3.2 
0.8 
1.1 

0.9 
1.3 
1.2 

1.0 

0.7 

0.6 

0.7 

2.6 

0.5 

1.4 

2.6 

1.0 

0.7 

0.7 

2.1 

0.8 

0.5 j 



per cent 
0.7 
1.1 

0.6 
0.7 
0.4 
0.4 
0.6 
0.5 
0.1 
0.1 
0.2 
0.2 

0.8 

0.7 

0.1 

0.1 

0.7 

0.3 

1.3 

0.7 

0.2 

0.3 

0.1 



CALORIES 
PER 100 GRAMS 



Raw 



22.7 
72.4 
71.8 
344.4 
42.4 
47.2 
33.2 
17.9^ 
34.5 
6.7^ 
31.2 
21.1 
23.3* 
368.8 
28.4 
82.5* 
329.9 
102.7 
109.5 
109.5 
24.4 
36.1 
14.8 



Cooked 



18.1 
45.3 
27.1 
60.7 
17.4 
14.1 
22.6 
30.1 
4.6 
16.7 
6.2 
3.7 
38.6 
121.9 
4.2 
8.2 
139.7 
30.6 
84.1 
78.5 
2.9 
4.6 
0.8 



^ * Evidently a misprint, for this number does not correspond to the analysis for pro- 
tein, fat, and carbohydrate printed in the table from which this is an abridgment. 

t It is not clear whether the raw and cooked cabbage were from the same or from dif- 
ferent varieties. 

Maurel and Carcassagne^ found that blanching for 30 minutes (or 15 
minutes? the two reports conflict) in distilled water, removed 40 per 
cent of the total salts from cauliflower, 44 per cent from Brussels sprouts, 
55 per cent from cabbage sprouts, 26 per cent from celery root (celeri 
pied), 37 per cent from celery leaves, 35 per cent from asparagus, 34 
per cent from green beans, 19 per cent from white beans, 3Z per cent 
from lentils, 61 per cent from potatoes. Amounts of potassium lost were 
in all these cases, except two, relatively high, ranging from 25 to 73 per 
cent of total potassium. In general, 40 to 50 per cent of total salts (50 



Compt. retid. Soc. Biol., vol. 67, p. 91, 211, 1909. 



8 THE JOURNAL OF HOME ECONOMICS [April 

to 75 per cent of total potassium) was lost in this blanching process. In 
the case of legumes, 30 minutes' blanching removed a much larger 
amount of potassium (73 per cent in white beans, 38 per cent in lentils) 
than did the remainder of the three hours' cooking (16 and 22 per cent, 
respectively). These authors also quote Laborde^" as fhiding a loss of 
75 per cent total salts (60 per cent of potassium) in the blalnching of 
cabbage; and LabiJle^^ as reporting losses of 29, 70, and 54 per cent of 
total potassium for 5 minutes' blanching of green beans, sorrel, and 
spinach, respectively; also, loss of 36 per cent of potassium in 10 minutes' 
blanching of potatoes. 

Poppe^^ cooked (or soaked) fresh green peas in two and one-half times 
their own weight of water or liquid, for 1 hour at 100°C., for two hours 
at 50°C., for 24 hours at 20°C. They used seven Kquids — distilled water, 
saturated NaCl solution (56 per cent), half-saturated, and quarter-sat- 
urated (10 per cent NaCl), saturated sugar solution (about 105 per 
cent), half -saturated, and quarter-saturated (18.4 per cent). They 
found that the peas boiled in distilled water lost 10 per cent of their ni- 
trogen (it seems the raw peas contained 19 per cent of protein), 13.6 per 
cent of their carbohydrate (6.92 per cent carbohydrate in raw peas), 3.9 
per cent of their phosphorus (0.66 per cent in raw peas), none of their 
chlorine. The salt solutions removed less of the nitrogen than did dis- 
tilled water, and very little phosphorus or carbohydrate ; the stronger salt 
solutions removed less nitrogen, in general, than did the weaker, but 
there was little difference in their extractive effect on carbohydrate. 
All losses were, as a rule, greater at the higher temperatures, because 
these kill the protoplasm and convert it from a semi-permeable mem- 
brane to a permeable one, whereas at 20°C. the hving protoplasm, 
though it imbibes water, is able to regulate its loss of solutes and the 
entrance of solutes from its environment, to a considerable degree. The 
peas took up about 1 per cent of their own weight in salt from the 
boiling quarter-saturated salt solution, and about 1.5 per cent of their 
own weight of sugar from the boiling quarter-saturated sugar solution. 
It is not stated whether the solutions were kept at their original strength 
by renewal of water as they boiled, or whether they became more con- 
centrated as cooking proceeded. Unfortunately these most careful and 
scientifically made observations can apply only somewhat remotely to 

lo^oc. d. Hist. nat. Tou-l., March 28, 1900, p. 67. 
" Traile de V Alimentation, vol. 3, p. 522, 44, 35. 
^Bul. Soc. chim. Belg., vol. 25, p. 136, 1911. 



1919] CHANGES IN FOOD VALUE OF VEGETABLES 9 

the problem of cooking losses, since solutions as strong as these could 
not be used in preparing vegetables. 

Berry'* found that boiled spinach lost 50 per cent of its salts; boiled 
cabbage 40 per cent; boiled carrots (cut in pieces) 11.5 per cent of their 
salts (23 per cent of phosphorus) and 26 per cent of soluble carbohydrate. 

Berg'^ suggests that in some cases the losses in alkali as a result of 
boiling vegetables are so great that the vegetable may actually lose its 
basic ash, and come to possess an acid ash. 

Bodinus'^ announces that the loss of solids in boiled potatoes is at 
least 2 per cent if pared. If sodium chloride be added to the water, the 
loss is 1.25 per cent of the starch and 10 per cent of the potato salts; 
if no salt is added, the potato loses 33 per cent of its salts. 

Morgan^^ reports a smaller loss of salts in peas canned by the com- 
mercial process than in those canned by the three-day sterilization home 
process. (Specifications and detailed results not given.) She found a 
loss of 18 per cent of the ash (25 per cent of phosphorus) due to blanching. 

Blunt and Otis^^ boiled 5 to 10 grams of spinach, string beans, navy 
beans, and peas, respectively, in 25 to 75 cc. distilled water in a covered 
beaker for 20 to 40 minutes (navy beans two hours) ; potatoes were also 
boiled (seven were scraped, cooked together, and mixed). These vege- 
tables, both raw and cooked, and the cooking water were then analyzed 
for iron. The losses found were: spinach, between 43 and 50 per cent of 
its total iron; string beans, between 39 and 43 per cent; navy beans, 
between 32 and 39 per cent; peas, 36 per cent; potatoes, between 15 and 
22 per cent. 

Visawanath^^ found that neutral salts (of calcium, magnesium, and 
sodium) retard, and alkaline salts (e.g., Na2C03) accelerate the cooking 
of legumes (dhall) because they retard or accelerate respectively, the 
solution of protein and starch, but more especially of protein. 

Courtney, Fales, and Bartlett^^ cooked seven varieties of vegetables 
by "thorough boiling" for 30 to 150 minutes, and analyzed cooked vege- 
tables and cooking water for calcium, magnesium, phosphorus, chlorine, 

" Jour. Home Econ., vol. 4, p. 405, 1912. 
" Nahrimg. u. Genus smiltd, Aschhcslindleile, Dresden, 1913. 
1^ Chem. Zentr., Bd. 2, p. 37, 1915. 
1^ Jour. Home Econ., vol. 7, p. 72, 1915. 
" Jour. Home Econ., vol. 9, p. 213, 1917. 

18 Mem. Dept. Agri., India, Chem. Ser. 4, No. 5, p. 149, 1916. Abstr. from Chem.Abstr., 
1917. 

'9.4/«cr. Jour. Dis. Children, vol. 14, p. 34, 1917. 



to THE JOURNAL OF HOME ECONOMICS [April 

potassium, sodium, sulphur, iron, and nitrogen. The percentage losses 
on most salts were greater than losses in calcium and nitrogen. New 
Zealand spinach was an especially heavy loser (72 per cent of total ash), 
yet it lost very Httle of its calcium, and the same thing was true of ordi- 
nary spinach. (Both these vegetables are especially good sources of 
calcium, if one were to judge from chemical analyses alone, — a ques- 
tionable proceeding.) Carrots, onions, and asparagus lost but a trace of 
iron; spinach, 28 per cent of its iron; New Zealand spinach 51 per cent. 
Reducing the time of cooking made little difference in the losses (spinach 
cooked 10 minutes instead of 90, string beans cooked 60 minutes instead 
of 150 minutes lost almost as much as before). Steaming, however, 
reduced the losses materially (spinach only half as much loss as when 
boiled, asparagus one-third as much, carrots one-fourth as much). New 
Zealand spinach and onions still lose 20 to 30 per cent of their more 
soluble constituents, when steamed (for 30 minutes). 

WeibulP" concludes that while potatoes do not lose appreciably if 
boiled in their skins, they lose 0.5 per pent of their solids if pared before 
boiling. If sweetened by chilling, they lose 0.5 per cent when boiled in 
skins, 1.5 per cent when pared before boiling. Cooked in hard water, 
they retain their solanin; cooked in distilled water, they lose one- third 
of it. 

Wardall,^^ working to develop a method of making vegetables free of 
digestible carbohydrate for the use of the diabetic, placed the finely cut 
vegetables in cold water, brought this to the boil, boiled for several 
minutes, then poured the water off and repeated the process. She found 
that, while beets give a test for reducing sugar after two such extrac- 
tions and are then exhausted of such carbohydrate, cabbage still gives 
the test after 8 extractions, carrots after 6, eggplant after 7, parsnips 
after 6, pineapple after 9. Extracted in water at 60° C, 1 hour was re- 
quired to extract all reducing carbohydrate from beets; 1| hours for 
carrot; 2 hours for eggplant; 1 hour for parsnips; 3| hours for pine- 
apple. Cabbage seemed to give up little of its reducing substance to a 
60°C. extraction. 



^°Ktmgl. Landtbruks-akad. Handling ar Tidskrijt, vol. 56, p. 348, 1917. Abstr. in Chem. 
Abstr., 1917. 

'^ Jour. Amer. Med. Assti., December 1, 1917. 



1919] CHANGES IN FOOD VALUE OF VEGETABLES 11 

t Masters^^ tried the effect of boiling dried beans in a large excess of 
water (five times their own weight) treated in various ways. She found 
that soaking the beans overnight reduced the time of cooking only from 
2 hours and 5 minutes to 2 hours. (The experience of the author of 
this paper is very nearly in accord with hers, though there is a good 
deal of variability among the different kinds and different grades of 
maturity. If the beans be put directly into boiHng instead of into 
cold water to cook, the time is still further reduced in some instances.) 
The soaked beans lost a larger proportion of their solids than did the 
unsoaked (12.2 per cent instead of 10.5 per cent in tap water; 12.6 
per cent instead of 11.1 per cent, in distilled water). Salting the 
water reduced the losses considerably: in 0.25 per cent NaCl, they 
lost 9.2 per cent of their solids; in 0.5 per cent NaCl, 8.7 per cent; 
in 1 per cent NaCl, 8.3 per cent. Even the salts of tap water had a 
slight effect in this respect (11.1 per cent loss when boiled without 
soaking, instead of 10.6 per cent loss in tap water), when soaking and 
cooking were not too much prolonged. Adding soda increased the losses ; 
boiled (without soaking) in 0.1 per cent solution of sodium bicarbonate 
in tap water, they lost 11.3 per cent of their solids; in 0.25 per cent 
solution, 14.3 per cent; in 0.5 per cent solution, 22.3 per cent; in 1 per 
cent solution, 27.3 per cent. Disintegration was very rapid at the 
higher concentrations, and the flavor was such that the beans were 
uneatable; the most ..satisfactory results were those when 0.1 per cent 
sodium bicarbonate was used. 

Cooking by steaming was also tried; 100 grams beans were covered 
with 250 grams boiling water, the basin was placed quickly in a steamer, 
and closed with a tightly fitting Kd. When thus steamed witliout pre- 
vious soaking, they lost 8.9 per cent of their soHds; soaked overnight and 
thus cooked, they lost 10.4 per cent; cooked (without soaking) in 0.25 per 
cent NaCl, they lost 8.4 per cent; cooked (without soaking) in 0.1 per 
cent sodium bicarbonate and 0.25 per cent salt, they lost 7.8 per cent; 
cooked in 0.1 per cent soda and 0.25 per cent salt after previous soaking 
they lost 8.1 per cent of their original weight. 

Denton and Kohman^^ fed young white rats raw carrots, boiled 
carrots with the concentrated cooking water, boiled carrots without 

t This thesis was prepared in March 1918. The foUomng notes were added in March, 
1919, in order to bring the bibliography up to date. 
22 Biochem. Jour., Oct., 1918. 
2' Jour. Biol. Chcm., vol. 36, p. 259, November, 1918. 



12 THE JOURNAL OF HOME ECONOMICS [April 

the cooking water, and canned carrots (processed two hours in 
boiling water bath). During the short period (five weeks) when 
carrots formed the sole diet (except for certain salts which were 
added), it was clear that those animals fed on raw carrots had the 
advantage over the others. Difficulties which the animals had in 
accommodating themselves to the unsuitable diet appeared to be 
greater, in proportion to the length of time the carrots had been cooked. 
However all animals ralUed and began to improve in time, except those 
on the canned carrots, who were started later than the rest and had not 
sufficient time to show what they could do before a change in diet was 
made. When protein, fat, and starch were added to the diet in such 
proportions that the carrots furnished only one-half to two-thirds of 
the solids and of the calories of the diet, cooldng of the carrots seemed 
to have no deleterious effects. True, however, it was observed that 
those animals which received carrots with the concentrated juice cooked 
down to some degree of caramelization did, after a time, fall considerably 
behind the rest in food consumption and also somewhat in rate of 
growth. The reason for this difference, which was perfectly apparent 
to all those who handled the animals and their food, cannot be stated, 
so far as I know, at the present moment. 

Those animals fed boiled carrots without the juice, on the other hand, 
developed unusually large appetites, though their growth curves were not 
quite as good as those of animals similarly fed on raw carrots. Presum- 
ably this shows the effect of the loss of a considerable portion of the 
caloric value of the vegetable into the cooking water. 

Daniels and McClurg^* fed young white rats on a diet in which cab- 
bage (raw, or boiled in water or in soda and water, or autoclaved) was the 
only source of water-soluble vitamine. The cooking water was in- 
clued in the diet in all cases. If my method of figuring this dietary is 
correct, the cabbage of these diets furnished 15 per cent of the calories; 
250 grams of cabbage were used to 100 grams of dry ration (casein plus 
starch plus salts plus fat). The soda was added in the proportion of 
1| teaspoons per cup of raw beans {33 cc. of 5 per cent solution of so- 
dium bicarbonate to 50 grams of soy beans); and 1| teaspoonful to 1 
pound of cabbage (63 cc. of 5 per cent solution, to 250 grams cabbage) ; 
this proportion of soda is about what is very commonly used in cooking 
these vegetables. Their experiments continued only through one month 

^* Jour. Biol. Ckem., vol. 37, January, 1919. 



1919] CHANGES IN POOD VALUE OF VEGETABLES 13 

in the case of cabbage feeding; but it is believed that the effects of a 
decided deficiency of water-soluble vitamine should be apparent within 
that time. Yet animals on all of these cooked diets throve equally well 
with those fed raw cabbage, and all animals kept pace with or exceeded 
the normal rates of growth. Evidently, then, cooking of cabbage even 
at high temperatures or even in alkahne medium did not sufficiently 
impair the water-soluble vitamine so that growth was perceptibly 
interfered with, under the conditions above described. 

It must, however, be noted with respect to the last two investigations 
reported, that it is possible the results might have been slightly dif- 
ferent if the amount of vegetable fed had been reduced to the minimum, 
or that which would furnish barely sufficient vitamine to meet the needs 
of growth. In case cooking does have a slightly prejudicial effect on 
vitamines, it would be more Hkely to appear when the margin of safety 
is a narrov/ one than when it is a very wide one. It may be added, 
that tlic am.ounts of vegetables fed (especially in the carrot diets) in the 
diets described above are larger, proportionately, than is usually con- 
sidered possible in human dietaries. Even in the case of the cabbage 
diets, it will be observed that the vegetable furnishes 15 per cent of the 
calories; this would call for 2.45 pounds edible portion, or 2.91 pounds of 
cabbage as purchased, in the 2500-calories-a-day dietary; or 2.94 
pounds edible portion, or 3.48 pounds as purchased, in the 3000 calorie 
diet of man. 

As Miss Daniels remarks, this excessively wide margin of safety in 
respect to vitamines may perhaps account for the fact that her results 
are different from those of McCollum and co-workers (Jour. Biol. 
Chem., Vol. 33, p. 55) who found that the water soluble vitamine 
extracted from the wheat embryo was apparently destroyed by 60 
minutes boiling in alkaline medium. 

Stanley-^ gives tables showing losses due to blanching varying from 
19 per cent in wax beans to 53 per cent in cabbage. Another table 
shows 52 per cent of mineral matter lost in boiled spinach, 9 per cent 
in steamed; 41 per per cent in boiled cabbage, 11.5 per cent in 
steamed. Details of manipulation are not given. 

III. PURPOSE OF THIS INVESTIGATION 

This work was undertaken with a view to determining how great are 
the variations in food value resulting from different methods of house- 

2s Cooking of Vegetables. Cir. 1, Agr. Ext. Service, Univ. of Mo., 1915, 



14 THE JOURNAL OF HOME ECONOMICS [April 

hold manipulation, in any given process of cooking. The process most 
frequently studied was that of boiling vegetables. The details consid- 
ered cover such points as those mentioned on page 3 of the introduction. 

rV. METHODS 

The methods which were used by the writer in cooking these vegetable 
samples are described in the tables given below. After cooking, the 
vegetable was ground or mashed or thinly sliced into lead caps or on to 
glass plates, and dried at 30° to 80°C. in an oven, or warm air blast, 
or over a water bath. The amounts of vegetable cooked were ordinarily 
between 50 and 100 grams, or often much more. This amount was 
necessary in order that the process should have some resemblance to the 
ordinary household process; also, in order to secure an approach to 
homogeneity of samples. After drying, the samples were finely ground 
for burning in the bomb calorimeter. Often they were formed into pel- 
lets by hammering against a metal rod in a m.etal tube. This was done 
in order to prevent scattering when the first rush of oxygen enters the 
bomb; usually, however, this precaution was unnecessary. 

The control (uncooked vegetable) was always taken from the same lot 
as were those that were cooked. As individual specimens, even from a 
given lot, may often vary considerably among each other in water con- 
tent and consequently in percentage composition, the control was, 
whenever possible, a part of the same individual vegetable specimen. In 
cutting the samples used as controls (uncooked), pains was taken to 
secure strips running lengthwise through every region of bud or root- 
stock, so that proportionate amounts of cortex, pith, fibro-vascular 
bundles, parenchyma, or growing region, would be about the same in 
control as in other samples. Where it was necessary to take transverse 
sections, these were selected alternately from the various regions, so that 
each sample might contain representatives or every region. 

Combustion was conducted in a platinum or nickelled capsule, by 
means of a Riche adiabatic bomb calorimeter (vacuum insulation; igni- 
tion by means of linen thread instead of iron wire was frequently used). 
A differential thermometer was read so as to show differences in tem- 
perature of 0.001°C. Bomb calorific values are thus obtained directly, 
for the dried material. 

It is not practicable to give calorific values in terms of weight of 
cooked vegetables, since this weight varies enormously according to the 



1919] CHANGES IN FOOD VALUE OF VEGETABLES 15 

details of manipulation, and varies, indeed, from moment to moment 
as the steaming vegetable cools and loses water. I have therefore cal- 
culated all values for cooked vegetables upon the basis of raw weight. 
For example, suppose that 100 grams of raw parsnips weigh 95 grams 
after cooking (at the moment of manipulation), which dry down to 20 
grams; and that this dried parsnip shows a caloric value of 4000 (gram- 
calories) per gram. Then the raw vegetables with a corresponding 
value should be assigned 20 per cent of 4000 calories, or 800 gram- 
calories per gram; which is 363 kilo-calories per pound. If the control 
or uncooked parsnip shows a value of 1000 gram-calories per gram of 
fresh vegetable (or 454 kilo-calories per pound), then it is evident that 
this parsnip has lost 20 per cent of its caloric value in the cooking 
process. 

DupKcate samples taken from the same vegetable specimen (or from 
the same lot if of very small size, as peas) should check within 2 or 3 
per cent at farthest. A closer check (0.5 per cent) is usual, but not 
always possible with raw vegetables, because of the lack of homogeneity 
of the material. When a high salt content (spinach, some beans) inter- 
feres with complete combustion in the calorimeter (by the fusing of salts 
so as to encase carbon particles and protect them from combustion), 
the difficulty may sometimes be remedied by spreading the dried pow- 
dered sample over a piece of filter paper, whose dry weight and caloric 
value per gram are known, rolHng the whole like a cigarette and be- 
stowing it in the capsule for combustion. Substracting the calories due 
to the filter paper, one has then left the calories due to the dried vege- 
table. Usually, however, if the linen thread (instead of the iron wire) 
be used for igniting, there is no difficulty. 

Furthermore, the calorie value of the total cooked sample plus the 
calorie value of the concentrated cooking water must be approximately 
equal to the calorie value of an uncooked sample of the same size, as 
calculated from the control. This check was conducted in a number of 
instances (though by no means in case of all samples reported) by 
evaporating the cooking water to a few cc. of sirup, taking it up on 
a weighed piece of filter paper of known calorific value, drying and burn- 
ing the whole mass together, or in fractions, as might be necessary. In 
those cases where the amount of extract is too great to be concentrated 
into a volume convenient for such a test, it may be dissolved in a rela- 
tively large volume of water (e.g., 100 to 250 cc), mixed until thoroughly 
homogeneous, and divided into aliquot portions in any convenient 



16 THE JOURNAL OF HOME ECONOMICS [April 

manner. One of these portions is then concentrated, collected, dried, 
and burned as above. Any suspended particles must be allowed to 
settle, and then be filtered out of the whole sample before division into 
aliquots, finally to be dried and burned separately. 

Doubtless the question will suggest itself, why should so large a per- 
centage of these determinations have been made with carrots and pars- 
nips? The reasons were that their cheapness (price per pound) and the 
ease with which they are stored have put them into general use; that 
they are usually pared and cut before cooking, largely as a matter of con- 
venience to the cook; that their high sugar content makes them sensi- 
tive indicators upon which the effect of vaiying manipulations may be 
detected. 

Total salts were determined by the water-leaching method (Official 
Methods, Association Official Agricultural Chemists, Bureau of Chem- 
istry, Bulletin 107) ; ignition in muffie furnace. 

VI. DISCUSSIONS AND CONCLUSIONS^^ 

1. The vegetables experimented on, when boiled until tender in ex- 
cess of water which is thrown away, lose from 15 to 60 per cent of their 
fuel value. (It is a very simple matter to demonstrate these losses 
ocularly, by cooking pared parsnips, pared carrots, some varieties of 
peapods, cabbage, onions, etc., finely cut or even coarsely cut, in plenty 
of water, and then concentrating this water, after pouring off, to small 
bulk, when it takes the form of a molasses.) 

The losses are, of course, less, proportionately, when there is less soluble 
matter to lose. Turnips, cabbage, cauliflower, young carrots, aspara- 
gus, onions, spinach, peas, string beans, lose less than do parsnips and 
mature sweet carrots and Brussels sprouts (compare C III, 2, also C 
IV, 3, with C I and C II). Apparently carrots have their carbohydrate 
more largely in soluble form, than do parsnips, for their losses are pro- 
portionately heavier, under the same treatment, especially in those cases 
where their calorie values at all approach those of parsnips. (See P II, 
6 and C I, 6.) 

2. The losses in salts in every case except one (Spinach I, 2 steamed) 
parallel the calorie losses, and usually rather closely. They are, as a 
rule, slightly greater than the calorie losses. (The same thing was true 
of nitrogen losses, in those cases where such determination was made.) 

2** References are to table 1, unless otherwise stated. 



1919] 



CHANGES IN FOOD VALUE OF VEGETABLES 



17 



TABLE I 
Losses in cooking vegetables, caloric values 







fe o 


s 


o n H 


o o b 


X 






is 


< 


www 


H w n 








06 


MHO 
O "S H 


o < ri 


H 










O -1 w 


O 1-1 g 




SERIAL NUMBER 


MANIPULATION 




«3 

p< < 

H 

5a 


W i-l > 

> B 2 


b i-l ^ 

O < < 
u en 

g m O 

>-' CJ « 


>^ 

c^ 

w 

H 
H 

< 






n u ;<4 


is 


ai W '^ 


OS Id 0. 






o o o 


O o « 










5 w o 




►J w w 




>J o 






«>u 


s° 


<>B. 


<>». 


S" 


Peas, I. 


Young green, purchased May 9, 1917 


; pods well filled, peas quite juicy 



Peas I, 1 
Peas 1,2 



Uncooked.* 

82 grams vegetable blanched 4 min- 
utes in 400 cc. salted distilled wa- 
ter (1.4 per cent); cold-dipped un- 
der running tap. Then placed in 
80 cc. boiling salted distilled water 
(1.5 per cent); boiled twenty min- 
utes; peas had taken up all the wa- 
ter. Washed in 90 cc. distilled wa- 
ter, brought to boil in four and one 
half minutes, then drained off. 
Weight, after cooked, 90 grams. 



25.50 
24.97 



gram- 
calories 

4102 
4139 



gram- 
calories 

1044 
1033 



kilo- 
calories 

473 
469 



per cent 



0.8 



Peas, II. Young green, purchased June 5, 1917; pods filled with varying sized peas, some 

large ones 



Peas II, 1 
Peas II, 2 



Peas II, 3 



Peas II, 4 



Uncooked.* 

102 grams raw vegetable blanched 
six minutes in 500 cc. boiling dis- 
tilled water; cold-dipped under 
running faucet. Weight, after 
cooled, 106 grams. 

115 grams raw vegetable blanched 
six minutes in 500 cc. boiling salted 
distilled water (1.4 per cent); cold- 
dipped. Weight, after drained and 
cooled. 111 grams. 

103 grams raw vegetable blanched 
six minutes in 500 cc. boiling tap 
water; cold-dipped. Drained, and 
cooled, weight = 106 grams. 



26.16 


4249 


1112 


504 


21.99 


4270 


939 


426 


24.4 


4212 


1028 


466 


22.6 


4288 


969 


440 



15 



13 



* Omit word "cooked" throughout, in reading column headings, for this sample. 



TABLE 1— Continued 



SERIAL NUMBER 



MANIPULATION 



»2 



S « R 



pa '^ 

I. < D 
£^ H W 



p« J ^ 



Q o S 

8ps 



& mS 

»-5 w * 

< 3 S 

> B g 

w ?* S 

M H ? 

WW* 
O O « 
iJ W W 

< > a. 



ft ^ 
o o 

h) O 



String Beans, I. Young green, purchased May 9; strung, cut into half -inch lengths 







grams 


gram- 
calories 


gram- 
calories 


kilo- 
calories 


per cent 


S. B. I, 1 


Uncooked.* 


10.16 


3960 


402 


183 




S. B. I, 2 


80 grams raw vegetable blanched 
five minutes in 500 grams salted 
distilled water (0.2-4 per cent salt), 
cold-dipped. Drained, cooled, 99 
grams. 


9.317 


3750 


349 


159 


13 


S.B.I, 3 


71 grams raw vegetable blanched 
five minutes in 500 grams boil- 
ing distilled water, cold-dipped. 
Drained, cooled, 92 grams. 


8.43 


4046 


341 


155 


15 



String Beans, II. Young green, purchased June 5; "strung" and cut into half-inch lengths 



S. B.II, 1 
S. B. II, 3 



S. B.II, 4 



S. B. II, 2 



Uncooked.* 

80 grams raw vegetable boiled in 
500 cc. distilled water (0.4 per 
cent salt) for twenty minutes. 
Drained, cooled, weight = 89 
grams. (Not quite "done" 
enough to eat.) 

87 grams raw vegetable steamed 
twenty minutes on wire gauze, 3 
inches from level of boiling water; 
covered, but not perfectly tight. 
Drained, cooled, weight = 85 
grams. (Not quite "done" 
enough to eat.) 

199 grams raw vegetable autoclaved 
in wire basket twenty-five minutes 
at pressures between 10 and 15 
pounds; entire period of steaming 
in autoclave, forty-four minutes. 
Cooled, weight = 174 grams. 
Flavor unpleasant, like hay, other- 
wise tasteless; mealy texture. 



11.7 
10.16 



11.52 



11.04 



3768 
3890 



3872 



3862 



441 
395 



446 



436 



200 
179 



202 



198 



10 



1+, 
(gain)t 



*Omit word "cooked" throughout, in reading column headings, for this sample. 

t This apparent gain may probably be due to some error in determining the factor noted 
in the third column. The sample used for drying was an unusually small one. Or, it may 
be due to lack of homogeneity in raw materials. 

18 



TABLE 1 — Continued 







Sa 

n 

"1 ^ 

S w R 
•< S w 


a 


Q O H 


Q n H 








^ 


WWW 
MHO 


H H n 
;^ H o 


HI 






Pa ,_] 

p. < 

5> 


S p s 

ft ■-> 5 

o < 5 


§23 

o 3 =: 
o < < 


o 

g 


SERIAL NUMBER 


MANIPULATION 




H W O 
< hJ 5 


< 3 9 


5 

s 






Q 


> « 3 


> B g 


<-> o 






w w a 


« 3 
o a 


w < 5 

S H O 
a W B< 








2 o o 


o o « 


O O oi 


o o 






a w o 


►J w w 


h) 14 M 








g>a 


<>A. 


<>0. 


3" 



String Beans, II. (Continued) 



S. B. II, 5 



159 grams raw vegetable in pint jar 
with 260 grams water and 1.7 
grams salt, cover screwed down; 
cooked in autoclaved run as de- 
scribed in S. B. II, 2, above. Jar 
was opened fifteen minutes after 
removal from autoclave; tempera- 
ture of contents, 90°. Drained 
and cooled, beans weighed 191 
grams. Flavor of beans and of 
juice, fairly good; juice rather 
cloudy. 



grams 
9.535 



gram- 
calories 

3785 



gram- 
calories 



361 



kilo- 
calories 

164 



Per cent 

18 



String Beans, III. Purchased March 18, 1918. Green, tender. "Strung," cut into finch pieces 



S. B.III, 1 
S. B.III, 2 



Uncooked.* 

133 grams raw vegetable boiled 
thirty minutes in 700 cc. tap wa- 
ter; cooking water at end of proc- 
ess, 350 cc. Weight of beans 
after cooked, 150 grams. 



9.8 
6.646 



3926 
4120 



387 
274 



176 
123 



30 



Spinach, I. Purchased March, 1918. Somewhat stale. Not v/ashed 



Spin. I, 1 


Uncooked.* 


8.636 


3491 


302 


137 




Spin. I, 2 


1 1 1 grams of raw vegetable steamed 
seventeen minutes on false bottom 
over 150 cc. water. Drained and 
cooled, 107 grams. 


8.180 


3257 


266 


121 


12 



Spinach II. Purchased April, 1918. Fresh 


. W^ashed with ordinary care 


Spin. II, 1 


Uncooked.* 


8.235 










Spin. IT, 2 


205 grams boiled twenty- five min- 
utes in 3000 cc. tap water (2200 cc. 
at close). \\'eight after cooled 
and drained, 168 grams. 


5.200 










Spin. II, 3 


200 granis steamed twenty-five min- 
utes on wire gauze. Weight after 
drained, 169 grams. 


7.450 











*Omit word "cooked" tliroughout, in reading column headings, for this sample. 

19 



20 



THE JOURNAL OF HOME ECONOMICS 



[April 



TABLE I— Continued 



SLRIAL NUMBER 



MANIPDLATION 



< 2 


s 


a Q 


Q Q b 


< 


u o S 


H M n 

MHO 

°u 

U > 


^ OS 
H (-, W 

n M M 


« 1-1 


£S 


P^ ^ w 


p-^5 

o < •< 


i-l M 

-< > 

ii 


►J (d « 

< iJ « 


as® 
< ij g 

> « z 

oi H 0< 


O o o 


o o 


O O OJ 


O (^ 


3 wo 




>J H H 




5° 


<>a, 


g>P. 



a 

O o 

G 2; 
S3 

o o 

•i ° 

< u 



Cauliflower, I. Half-pound head. 



Leafy bracts and petioles tender green, 
vertically 



Head divided 







grams 


gram- 
calories 


gram- 
calories 


kilo- 
calories 


per cent 


Caul. I, 1 


Uncooked.* 


14.24 


3828 


545 


247 




Caul. 1,2 


55 grams raw vegetable boiled in 
500 cc. tap water (150 cc. at end of 
period) for fifteen minutes. Cold, 
drained, weight = 52 grams. 


10.26 


4059 


416 


189 


23 


Caul. I, 3 


50 grams raw vegetable steamed 
twenty-five minutes. Cold, 
drained, weight = 49 grams. 


14.36 


3773 


542 


246 





Caul. I, 4 


Outer leaf stalk only, uncooked.* 


15.02 


3702 


556 


252 




Caul. I, 5 


Outer leaf stalk only, 25 grams raw 
stalk boiled in same water with 
Caul. I, 2, above, for twenty-five 
minutes. Cold, drained, weight 
= 25 grams. 


11.60 


3671 


426 


194 


23 


Caul. I, 6 


Outer leaf stalk only, 15 grams 
steamed twenty-five minutes. 
Cold, drained, weight = 12 grams. 


12.60 











Brussels Sprouts, I. A good fresh green. A little dry 



B.S.I, 1 
B.S.I, 2 



B. S. I, 3 



B.S.I. 4 



Uncooked.* 

94 grams raw vegetable boiled 
whole, five minutes in boiling tap 
water (500 cc). Cooled, weight 
= 108 grams 

94 grams raw vegetable boiled 
whole twenty-five minutes in 500 
cc. tap water. Cooled, weight = 
112 grams. 

97 grams raw vegetable, each head 
cut lengthwise into three or four 
slices, boiled twenty-five minutes 
in 500 cc. tap water. Cooled, 
weight = 120 grams. 



17.055 


4154 


709 


322 


14.31 


4246 


608 


276 


10.96 


4539 


414 


ISS 


14.41 


4266 


615 


270 



14 



42 



13 



*Omit word "cooked" throughout, in reading column headings, for this sample. 



TABLE I — Continued 







& g 


^ 


Q Q 


Q Q H 










< 








S-iRlAL NUMBER 


MANIPULATION 


a 

a « Q 

< g w 
W w « 


O in 
H 

< > 


i^ H t^ 

§gi 

'.^ iJ > 
O < 5 

c> « -< 

►J W OS 

5 -J y 

> n a 


« H O 

° 3 3 

o < "^ 

r. <-» *= 
r<Sg 

> m 5 

2S§ 

« w f^ 


H 
O 

a 
E s: 








o o « 
























g>o 


a- 


2><. 


g>g 


S" 



Cabbage, I. Purchased January, 1918. Firm, white head about If pounds. Outer leaves 
missing. No green. Cut vertically 







grams 


gram- 
calories 


gram- 
calories 


kilo- 
calories 


per cent 


Cab. I, 1 


Uncooked.* 


7.914 


3803 


301 


137 




Cab. I, 2 


188 grams rav/ vegetable (one- 
fourth of cabbage head), steamed 
thirty minutes. Weight, after 
cooked and cooled, 175 grams. 


8.388 


3763 


316 


143 


4.4 

(gain)t 


Cab. I, 3 


203 gram.s raw vegetable (one- 
fourth of head), cooked thirty 
minutes in 1000 cc. boiling tap 
water (700 cc. at end of cooking 
period). Weight after cooked and 
cooled, 215 grams. 


5.835 


4-001 


234 


106 


21 


Cab. L 4 


180 grams raw vegetable (one- 
fourth of head), cooked thirty 
minutes in 1000 cc. boiling salted 
tap water (1.5 per cent salt); 750 
cc. at end of cooking period. 
Cooked and drained, 167 grams. 
"Cooked to pieces" more than 
Cab. I, 3 (which was a more com- 
pact piece). 


7.591 


3335 


253 


115 


14 



Cabbage, II. Purchased November, 1917. Small, compact, crisp heads; outer leaves pale 

green. Cut vertically 



Cab. II, 1 
Cab. II, 2 



Uncooked,* ground and dried. 

900 grams raw vegetable (one small 
solid head cut into eighths) 
blanched in 4500 cc. boiling tap 
v/ater ten m.inutes, then cooled un- 
der running tap. Packed tightly 
into quart jar, with hot water and 
10 grams salt. (57.5 grams re- 
maining as juice at end of process.) 
Tar processed two hours in bath of 
boiling water. Weight of drained 
cabbage, 797 grams. 



10.00 
10.107 



3809 
3664 



381 
371 



173 
168 



* Omit word "cooked throughout, in reading column headings, for this sam{)le. 
t This discrepancy is, so far, unexplained. 

21 



22 



THE JOURNAL OF HOME ECONOMICS 



[April 



TABLE I— Continued 



SERIAL NUMBER 



MANIPULATION 







Q Q H 


O Q H 


3 


HUM 


U H n 


SO H O 


WHO 






o < « 




w 


O >-l S 


o 1-1 S 


w 


OS i-i 


U D & 


b PS 


< U> » 


g? 


^a& 


^^S 


W W M 


o < < 


o <: < 


< > 


►J s o 

> B 5 


> 5 5 
S H ^ 


2 o o 


o o « 


O « 


S w o 


^s 


>J w w 


J W w 






O 


o 


o 



Cabbage, II. (Continued) 



Cab. II, 3 



Duplicate of Cab. II, 2, except not 
packed so closely. 276 grams of 
drained cabbage and 120 cc. liquid 
in pint jar. (375 grams of raw 
cabbage had been packed into it.) 



grams 

5.7 



gram- 
calories 

3654 



gram- 
calories 

209 



kilo- 
calories 

94 



per cen I 

46 



Onions, I. Ordinary yellow. Purchased February, 1918. Outer scaly leaves rejected 



0.1,1 
0.1,2 



0.1,3 
0.1.4 



O.I, 5 



Uncooked,* vertical halves of two 
onions. Control for O. I, 2. 

83 grams raw vegetable, vertical 
halves of same onions used for 
O. I, 1. Soaked twelve and one- 
half hours in 650 cc. water, after 
slicing horizontally (went all to 
pieces). Drained, weight = 104 
grams. Bud swelled, unequal tis- 
sue strains apparent. 

Uncooked,* lower half of an onion, 
same lot. Control for O. I, 4 (???) 

44 grams raw vegetable, upper half 
same onion as in O. I, 3. Soaked 
in 350 cc. salted tap water (two per 
cent salt) for twelve and one-half 
hours, having been cut into three 
horizontal slices. Held together 
fairly well; wilted, except for 
smallest inner bud. Drained, 
weight = 48 grams. 

68 grams raw vegetable, (1 onion), 
cut crosswise into halves. Boiled 
forty minutes in 1100 cc. tap water 
(700 cc. at end of period). 
Cooked and drained, weight = 
58 grams. Cooking water concen- 
trated, yielded 8438 kilo-calories. 



8.075 
7.394 



11.89 
9.527 



4.421 



3817 
3783 



3940 

3585 



•1007 



313 
280 



469 
342 



181 



142 
127 



213 
15.S 



cS2 



11 



27t 



* Omit word "cooked" throughout, in reading column headings, for this sample. 
t See p. 31 for discussion of comparison between O. I, 2 and O.I, 4. 



1919] 



CHANGES IN FOOD VALUE OF VEGETABLES 



23 



TABLE I— Continued 



MANIPULATION 



SERIAL NUMBER 



*2 


3 


Q H 

HUM 


O Q H 

82a 


n 


0) 


82i3 


iaS 


S" 


OPS 


OPS 


H W M 


eg 


o < 5 

r"^ i-i a 

ago 


O < 5 
< 3 Q 

M < P 

3 w 0- 


2 oo 


o o 


o a Bi 


O O M 


S H O 




H w w 


d w « 



O o 

o o 

>i o 

< o 





Onions, I. (Continued) 












grams 


gram- 
calories 


gram- 
calories 


kilo- 
calories 


per cent 


0.1,6 


50 grams raw vegetable (1 onion), 
boiled whole forty minutes in 1000 
cc. tap water (700 cc. at end of 
cooking period). Weight, after 
cooled and drained, 41 grams. 
Cooking water concentrated, 
yielded 6878 calories. 


6.868 


3842 


264 


120 


34 



Turnips, I. White, purchased January 15, 1917; 290 grams each. Pared, quartered length- 
wise, in T. I, 1 and 2 



T.I, 3 
T.1,1 



T.I, 2 



Uncooked.* 

61 grams raw vegetable cooked 
thirty minutes in 500 cc. boiling 
tap water. Weight, after drained 
and cooled, 57 grams. 

65 grams raw vegetable cooked 
thirty minutes in 500 cc. boiling 
salted tap water (1.5 per cent salt). 
W^eight, after drained and cooled, 
59 grams. (Water boiled almost 
dry.) 



5.29 


3850 


204 


92 


3.761 


4098 


154 


70 


6.041 


3283 


198 


90 



24 



Asparagus, I. Purchased March, 1918. Base of stems tough, trimmed off. 



Aspar. I, 1 
Aspar. I, 2 



Uncooked.* 

76 grams blanched five minutes in 

1000 cc. boiling tap water. 

Weight, after cooled and drained, 

76 grams. 



7.953 
7.185 



4068 
4139 



324 
297 



147 
135 



Asparagus, II. Purchased May, 1918. Trimmed, washed 



Aspar. II, 1 
Aspar. II, 2 



Uncooked.* 

69 grams cut into 1| inch lengths, 

blanched five minutes in 500 cc. 

boiling tap water. Weight, after 

drained, 71 grams. 



7.590 
7.597 



♦Omit word "cooked throughout, in reading column headings, for this sample. 



TABLE I— Continued 









> o 


s 


Q Q H 


Q a H 










< 2 


<: 


M M n 


M H P 














MHO 












a « Q 
< S w 




CJ P ? 
Cu 1-1 P 


2 3 i3 


o 


SERIAL NUMBER 


MANIPULATION 




2S§ 


p o 
< > 


O < < 

bj u as 

S J a 


< 3 Q 

> S z 


H 

H 

< 

a 








S W M 




W < M 


2 w 0- 


Sz 








2 o o 


o ^ 


O o Bj 


O O oj 


o o 








S w o 


iJ s. 


■J w w 




i-I o 








g>u 


<; o 


<: > p< 




















Parsnips, 11. 


Purdiased January, 1917. 


Medium size, pared, cut lengthwise into eighths. 






Wilted 













p. II, 8 
P. II, 7 



P. II, 6 



Uncooked.* 

Blanched five niinutes in 1000 cc. 
tap water; cold dipped; 86 grams 
of vegetables cooked twenty-two 
minutes in 1000 cc. hot unsalted 
tap water; weight, after cooking, 
83 grams. 

Blanched in 1000 cc. salted distilled 
water (ttt per cent salt) five 
minutes; cold dipped; 85 grams of 
vegetables cooked twenty-two 
minutes in 1000 cc. hot salted 
distilled water f-nj- per cent salt) ; 
Weight after cooking, 83 grams. 



26 
17 



20 



gram- 
calories 

3916 
4125 



3941 



gram- 
calories 

1018 
701 



788 



kilo- 
calories 



462 

318 



357 



per cent 



31 



23 



Parsnips, III. Purchased January, 1918. Medium size, badly wilted before used, pared 



P. Ill, 1 
P. Ill, 2 



P. Ill, 3 
P. Ill, 4 



P. Ill, 5 



Uncooked.* 

61 grams of raw vegetable (one half 
parsnip, cut lengthwise), cooked 
thirty minutes in 900 cc. boiling 
tap water. Weight, after cooked 
and drained, 68 grams. Control, 
P. Ill, 1. 

Uncooked* (second parsnip from 
same lot as P III, 1). 

58 grams of raw vegetable cut cross- 
wise from same parsnip as P. Ill, 3, 
alternately from top and tip; 
blanched three and one-half min- 
utes in 500 cc. boiling tap water; 
weight after cooked and drained, 
67 grams. 

50 grams raw vegetable, duplicate of 
P. Ill, 4, but cooked seven minutes 
in boiling tap, 500 cc. Weight, 
after cooked, 58 gram.s. 



31.38 


4450 


1396 


633 


26.57 


3967 


1054 


478 


38.11 


3912 


1491 


676 


26.93 


4013 


1081 


491 


25.26 


4027 


1018 


462 



25 



27 



32 



*Omit word "cooked" throughout, in reading column headings, for this sample. 

24 



1919] 



CHANGES IN FOOD VALUE OF VEGETABLES 



25 



TABLE I— Continued 



SERIAL mjMBER 



MANIPULATION 






H w 2 
2 o o 
B w o 



§2 



S ri s 

> M ^ 

H H "^ 

B« W O 

o o aJ 

J M W 

< > B. 



o q H 

ops 
o < < 

,., ^ « 



> P5 Z 

a w 0, 

O C5 M 

►J W W 



fa z 

as 



Parsnips, IV. Purchased February, 1918. Medium size, mature, unwilled, pared 



P. IV, 1 
P. IV, 2 



P. IV, 3 



P. IV, 4 



P. IV, 5 



Uncooked.* 

74.5 grams raw vegetable (one-half 
of same individual as P. IV, 1, cut 
lengthwise), cooked thirty-three 
minutes in 550 cc. boiling tap wa- 
ter (380 cc. at end of cooking 
period). Weight, after cooked 
and drained, 72 grams. 

33 grams raw vegetable (one-quarter 
of same individual as P. IV, 1, cut 
lengthwise). Cooked thirty- three 
minutes in 550 cc. boiling tap wa- 
ter (230 cc. at end of cooking 
period). Weight, after cooked, 
32 grams 

Uncooked,* second parsnip from 
same lot as P. IV, 1. Sliced cross- 
wise, slices taken alternately from 
top and tip. 

58.5 grams raw vegetable, duplicate 
of P. IV, 4, cooked thirty-three 
minutes in 550 cc. boiling tap wa- 
ter (310 cc. at end of cooking 
period). Weight, after cooked, 55 
grams. 



22.78 
18.77 



17.94 



21.42 



13.45 



gram- 
calories 

3858 
3989 



4118 



3987 



4022 



gram- 
calories 

879 
749 



739 



854 



541 



kilo- 
calories 

399 
340 



335 



387 



246 



per cent 



15 



16 



36 



Carrots, I. Purchased January, 1917. Mature, medium size, pared, and sliced crosswise. 

(Dry, slightly wilted.) 



C.I, 8 


Uncooked.* 


21.4 


3632 


777 


352 




C.I, 4 


70 grams of vegetable put into 500 
cc. cold distilled water; ten min- 
utes coming to boil; boiled twenty- 
five minutes. Weight cooked, 55 
grams. 


8.1 


3809 


308 


140 


60 



*Omit word "cooked" throughout, in reading column headings, for this sample. 



26 



THE JOURNAL OF HOME ECONOMICS 



[April 



TABLE I— Continued 



SERIAL NUMBER 



MANIPULATION 



te a 


S 


Q Q H' 


Q Q H 






M H m 


(d H d 


«w 




WHO 


WHO 




o < r! 


§3g 
O & S 




w 


5 ►J g 

U P P 


a « Q 
< S w 


U ►J 


U CR 


^^^ 


^a& 


Hi 




o < < 


o < << 


& o 


P m S 
►J w o 

< 1-1 a 

> pq 5 


H - h 

> n a 


M w a 


o o 


w ■< S 

S H p 

« w "• 


o o o 


O O M 


O O Bi 


3 w o 
g > o 


dBS 


iJ W W 


H w S 


d° 


g>B, 



O o 

H5 



Carrots, I. (Continued) 



C.I, 5 



C. I, 1 



C.I, 6 



87 grams of vegetable put into 500 
cc. cold distilled water; five min- 
utes coming to boil; boiled fifteen 
minutes. Weight cooked, 77 
gram.s. Water boiled away quite 
extensively. Not quite "tender." 

92 grams of vegetable put into 500 
cc. hot salted distilled water (1.5 
per cent NaCl), cold dipped. 
Boiled thirty-two minutes. 
Weight cooked, 88 grams. Boiled 
gently, water level not miuch low- 
ered at end of period. 

83 grams of vegetable blanched 
seven minutes in 500 grams, salted 
distilled water (1.5 per cent NaCl), 
cold dipped; boiled twenty-two 
minutes in 500 cc. hot salted dis- 
tilled water (1.5 per cent NaCl). 
Weight (cooked), 67 grams. Wa- 
ter boiled away quite extensively. 



grams 

12.0 



13.0 



12.0 



gram- 
calories 

3682 



2835 



3117 



gram- 
calories 

442 



368 



374 



kilo- 
caiories 

201 



167 



170 



per cent 
43 



53 



Carrots, II. Purchased April, 1917. Mature, pared, and sliced crosswise, unless otherwise 
designated. (Wilted somewhat.) 



C. II, 3 


84 grams vegetable cooked thirty 
minutes in 500 cc. boiling distilled 
water. Weight, after cooked, 93 
grams. Volume of water at end 
of process not observed. 


9.29 


3720 


346 


157 


56 


C. II, 4 


18 grams vegetable (one fourth 
carrot sliced lengthwise) cooked 
thirty minutes in 500 cc. boiling 
distilled water. Weight, after 
cooked 30 grams. 


15.44 


3724 


575 


261 


26 



Omit word "cooked" throughout, in reading column headings, for this sample. 



1919] 



CHANGES IN FOOD VALUE OF VEGETABLES 



27 



TABLE I— Continued 







< z 


a 
< 


H H Q 


w a a 


2 






K a 


a 




!<! H U 






















w 


5m K 




O 

Hi 






S§g 


t>i >-) 


U^> 


uu^ 






2 H H 


0, < 


fe d ^ 


fc. Hi S 










H 


o < < 


o <: < 


M 


SERIAL NUMBER 


MANIPULATION 




< > 

> Q 


< h) « 

> n 5 

S w" 
q o Bi 


> M 5 

oi W A. 

o o « 


2 S 






w S P, 


%o 


>j w w 


•-) H S 


►J o 






S>o 


3>B. 


<>P, 


5" 





Carrots, II. (Continued) 














grams 


gram- 
calories 


gram- 
calories 


kilo- 
calories 


per cent 


C. II, 6 


71 grams cooked vegetable which 
came from steam pressure insti- 
tutional cooker. Pared and 
sliced crosswise before cooking as 
usual. Weight, before cooking, 
unknown . f 


7.58 


3638 


276 


125 


65 



Carrots, III. Purchased May, 1917. Small, young, pared, and sliced crosswise 



C. Ill, 1 
C. Ill, 2 



C. Ill, 3 



Uncooked.* 

54 grams vegetables boiled in 500 cc 
hot distilled water for twenty- 
three minutes. Weight, after 
cooked, 57 grams. 

62 grams vegetable steamed thirty 
minutes over 1000 cc. water. 
Weight, after cooked, 57 grams. 



11.6 
7.002 



11.78 



3597 
3776 



3646 



418 
265 



416 



190 
120 



189 



37 



0.95 



Carrots, IV. Purchased January, 1918. Medium size, pared, and sliced as described 



C. V, 1 
C. IV, I 



Uncooked.* (Control for C. IV and 
C. V.) 

39 grams vegetable cut into length- 
wise slices, 10 grams each; 
blanched in 500 cc. boiling tap wa- 
ter, five minutes. Weight, after 
blanched, cold dipped and drained, 
36 grams. 



10.8 
6.885 



3618 
3788 



391 
268 



177 
118 



33 



* Omit word "cooked" throughout, in reading column headings, for this sample. 

t Steam cooked vegetables usually lose weight in cooking, but it may be that these pieces 
were so situated that they took up some water (condensed steam) which washed over them. 
In calculating this sample, the raw weight has been assumed to be identical with the weight 
after cooking. If the weight of raw vegetable was greater than the weight cooked, then the 
cooking loss is still greater than here calculated; if less, then the loss would be somewhat less. 



28 



THE JOURNAL OF HOME ECONOMICS 



[April 



TABLE 1— Continued 



SERIAL NUMBER 



MANIPULATION 



< s 


s 


Q a H 


o a H 


«i: 


W H « 


(4 H ta 




« H U 


« H O 


"[^ 


?^2S 


823 


a « o 

< w w 




fe h) & 


o ;S 


Swg 

Www 






o < < 


w w 

Ij w 
< > 


p (/ fc- 
►J H O 

< Hi a 

w 2 5 
3«" 


> » 5 
« w »< 


o o o 


o o « 


o o « 


S w o 
g > c^ 




•-) M H 






< > fti 













Carrots, IV. (Conlinutd) 



C. IV, 3 



C. IV, 5 



C. IV, 6 



34 grams vegetable cut lengthwise 
into strips of 10 grams each; 
cooked twenty-five minutes in 
boiling tap water, 500 cc. Weight, 
after cooked, 28 grams. Water 
cooked down to 180 cc. at end of 
cooking period 

72 grams vegetable cut lengthwise 
into 7 strips laid on wire gauze 
screening, autoclaved fifteen min- 
utes at 15 pounds; total length of 
time in autoclave, thirty-seven 
minutes. Weight, after cooked, 
55 grams. 

82 grams vegetable cut crosswise 
into 1 5 slices, autoclaved over wire 
gauze in same cooker and at same 
time as above. Weight, after 
cooking 61 grams. Surface ex- 
posed, considerably less than in 
C. IV, 5. 



grams 
5.027 



8.714 



8.834 



gram- 
calories 

4035 



3603 



3598 



gram- 
calories 

203 



314 



318 



kilo- 
calories 

92 



142 



144 



per cent 
48 



20 



19 



Carrots, V. Purchased January, 1918. Medium sized, pared, and sliced crosswise 



C. V, 1 
C. V, 2 



C.V, 3 



Uncooked.* 

46 grams vegetable put into 500 cc. 
salted boiling tap water (1.5 per 
cent), cooked thirty-sLx minutes. 
Weight, after cooked, 32 grams. 

51 grams vegetable put into 500 cc. 
unsalted boiling tap water, cooked 
thirty-six minutes. Weight, after 
cooked, 43 grams. 



10.8 


3618 


391 


177 


12.4 


2036 


252 


115 


5.945 


3725 


222 


101 



35 



43 



'Omit word "cooked" throughout, in reading column headings, for this sample. 



1919] 



CHANGES IN FOOD VALUE OF VEGETABLES 



29 



TABLE 1— Concluded 



SERIAL NUMBER 



MANIPLTLATION 



> o 


S 


Q Q H 


a o H 


? z 


< 


H w a 


H M n 

12 H o 


« w 








o < ti 


o < ri 




W 


O Hi w 


O Hi w 


S gR 




(J a is 






o . 




< W H 




t. i-I 5: 


h J 5= 


■^ < 


H 

H H 

i-l !4 

< > 


1-1 Id o 

f2w " 


O < < 

< 3 9 

> B 5 


Www 


5 2 


w ■< g 
S h O 
0- H a, 




O O 0! 


O O OS 


«^B 


d £• 


H W W 


>J w w 


3® 


g>». 



l_ o 

fa SS 

o o 

d o 



Carrots, VI. Purchased November, 1917. Fairly large, juicy; pared, and sliced crosswise 



C.VI, 
C. VI, 



C. VI, 3 



Uncooked.* 

700 grams vegetable blanched six 
minutes in about 5000 cc. boiling 
tap water; cold-dipped, packed 
tightly into quart glass jar; spaces 
filled with boiling water, cover and 
rubber gasket adjusted; jar set 
into boiling water bath covering 
it. Time of process, two hours. 
Water bath boiled away some- 
what, jar lost water, 2 to 3 inches 
space (and partial vacuum) above 
level of juice in jar when cold. 
Contents when opened, 699 grams 
of cooked and drained carrots, 
283 cc. juice. 

Duplicate of C. VI, 2, from different 
jar, 700 grams raw carrots; cooked 
and drained, 672 grams, 300 grams 
(290 cc.) of juice. 



11.56 
9.911 



8.024 



gram- 
calories 

3643 
3546 



3802 



gram- 
calories 



421 
351 



305 



kilo- 
cslories 



191 
159 



138 



per cent 



18 



28 



*Omit word "cooked" throughout, in reading column headings, for this sample. 

It is, however, the more soluble, rather than the difficultly soluble or 
insoluble carbohydrates and salts, which are the measure of available 
food; therefore the food losses exceed rather than run below the per- 
centage here stated. 

3. The "blanching" process as ordinarily used in home canning, 
causes losses of 8 to 15 per cent (Peas II, 2, 3, 4; Aspar. I, 2; Spin. I, 
2; Brussels sprouts I, 3; String beans, 1, 2, 3) and 27 to 33 per cent 
if vegetables are peeled and sHced (sliced parsnips, P III, 4 and 5) . These 
peas were blanched for 6 minutes, the string beans and carrots for 5 
minutes. The peas might have received a somewhat shorter blanch (2 
to 4 minutes), which would reduce their loss somewhat, but not propor- 



TABLE II 

Losses in mineral salts due to cooking 



Asparagus II, 1, raw 

Asparagus II, 2, blanched five minutes. 



Beans, String, S. B. Ill, 1, raw 

Beans, String, S. B. Ill, 2, boiled thirty minutes 



Brussels Sprouts, I, 1, raw 

Brussels Sprouts, I, 2, blanched five minutes.. 
Brussels Sprouts, I, 3, boiled twenty-five minutes 



Cabbage, I, 1, raw 

Cabbage, I, boiled thirty minutes tap . 



Carrots, II, 5, raw 

Carrots, II, 1, boiled thirty minutes. 



Cauliflower, I, 1, raw 

Cauliflower, I, 2, boiled fifteen minutes 

Cauliflower I, 3, steamed twenty- five minutes. 



Onions, I, 1, raw 

Onions, I, 2, soaked twelve hours. 



Onions, I, 3, raw 

Onions, I, 6, boiled forty minutes whole . 



Parsnips, III, 3, raw 

Parsnips, III, 4, boiled three and one-half min- 
utes 

Parsnips, III, 5, boiled seven minutes 



Peas, II, 1, green, raw 

Peas, II, 2, boiled in distilled water, six min- 
utes 

Peas, II, 4, boiled in tap water, six minutes. . . . 



Spinach, I, 1, raw, unwashed* 

Spinach, I, 2, steamed seventeen minutes. 



Spinach, II, 1, raw, washed* 

Spinach, II, 2, steamed twenty-five minutes... 
Spinach II, 3, boiled twenty-five minutes 



WEIGHT 

1 00 GKAMS 

VEGETABLE 

AFTER 

COOKED 

AND DRIED 



7.590 
7.597 

9.863 
6.646 

17.055 

14.31 

10.96 

7.786 
5.835 

14.21 
8.74 

14.24 
10.26 
14.36 

8.075 
7.394 

11.89 
6.868 

38.11 

26.93 
25.26 

26.16 

21.99 
22.6 

8.636 
8.180 

8.235 
7.450 
5.200 



ASH IN 

DRIED 

VEGETABLE 

MATERIAL 



Per cent 
8 ^.^ 

7.86 

5 . 897 
5.479 

6.50 

6.244 

5.10 

7.27 
7.18 

10.51 
6.80 

9.04 
6.91 
8.13 

3.17 
3.07 

4.70 
4.28 

4.84 

3.84 
3.42 

3.31 

3.27 
3.25 

23.66 
24.2 

24.34 
16.55 
12.42 



ASH CALCU- 
LATED 
TO FRESH 
WEIGHT 



per cent 
0.63 
0.60 

0.58 
0.36 

1.11 
0.89 
0.56 

0.57 
0.42 

1.46 
0.59 

1.29 
0.71 
1.17 

0.26 
0.23 

0.56 
0.29 

1.85 

1.03 
0.86 

0.87 

0.72 
0.74 

2.04 
1.98 

2.01 
1.26 
0.67 



per cent 



38 



20 
50 



26 



60 



45 
9 



12 



42 
54 



17 
15 



2.94 



37 
67 



*The determinations on spinach were made on washed and unv/ashed lots, after reading 
Rubner's statement (Berl. Klin. Wchnschrft. Apr. 10, 1916) that, owing to the cook's custom 
of washing spinach on one side of the leaf only, a large part of the "ash" is sand which clings 
to the leaves. This may have been true of the spinach which he analyzed, which showed 
half of the dry matter to be ash. 

30 



1919] CHANGES IN FOOD VALUE OF VEGETABLES 31 

tionately to the reduction in time of blanching, since the losses are rela- 
tively heavier in the earliest moments of the extraction period. (Com- 
pare Parsnips III, 4 and 5.) String beans, fresh prime stock, are often 
blanched even longer (3^ to 6 minutes or more) under trade conditions. 

4. The losses in blanching might be somewhat decreased by the 
use of a salted water. In case of peas the loss decreases from 15 per 
cent in distilled water (Peas II, 2 or 4) to 8 per cent in a 1.5 per cent 
salt solution (Peas II, 3); for string beans, from 15 per cent for dis- 
tilled water (S. B. I, 3) to 13 per cent for 0.25 per cent salt solution 
(S. B. I, 2) or 10 per cent loss on 20 minutes' boiling in 0.4 per cent salt 
solution (S. B. II, 3). Stronger solutions could well be used when short 
cooking is given. Here a slight increase in strength of salt solution 
has made more difference in amount extracted than has a fourfold in- 
crease in time. In case of longer boiling "until tender," the decreases 
in fairly comparable samples are: Parsnips, from 31 per cent in tap water 
(P II, 7) to 23 per cent (P II, 6) in 0.7 per cent salt solution; white 
turnips, from 24 per cent (T I, 1) to 2 per cent (T I, 2) in 1.5 per cent 
salt. See also Cabbage, 1, 3;, and 4. 

Boiled in a small amount of salted water, or in water which eventually 
boils down to a small amount, the losses are still smaller. See C VI, 2 — 
only 18 per cent loss, though they went through a 6 minutes' blanch 
before this long cooking period of several hours very near the boiling 
temperature. See also Peas I, 2, in which the salted water was entirely 
taken up; they apparently show less than 1 per cent loss, though they 
went through a 4 minutes' salt blanch before cooking. 

The difference in extractive power between distilled and tap water 
(Lake Michigan at Chicago), is evident but not great enough to be of 
practical significance (Peas II, 2 and 4). 

In comparing Onions I, 2 and 4, it should not be too hastily concluded 
that the effect of salt has been to increase the extraction. Unfortunately 
O I, 4 contains only the upper half of the bulb, and this may easily have 
been before soaking considerably lower in sugar than was the lower 
half (0 I, 3) from which the amount of extraction is estimated. 

5. Cooking losses are, of course, still further decreased by cutting the 
vegetable into large instead of into small pieces, particularly so if the 
cut runs parallel with fibro-vascular bundles rather than across them. 
Compare P II, and P III, 2, with P III, 4 and 5; 3| to 7 minutes extract 
as much from the cross-cut parsnip as do 30 minutes (or 27 minutes) 
from the lengthwise-cut parsnip. 



32 THE JOURNAL OF HOME ECONOMICS [April 

6. Steaming, if properiy performed, results in losses so small as to 
be ordinarily quite devoid of significance (Caul. I, 3; Spin. I, 2, table 
II, — ^but see also table I; Cab. I, 2; S. B. II, 4; C III, 3); this may be 
the case, even when the temperature is so high and the process so greatly 
prolonged as to result in serious detriment to flavor, as is possible in 
high pressure cooking (S. B. II, 2). However, this considerable period 
of steaming at higher temperatures than the boihng point is likely to 
extract a considerable amount of soluble material, when this is abun- 
dantly present (C IV, 5 and 6). Again, if the arrangement is such 
that steam condenses and water washes down over the heated vegetable 
tissue, the losses may be as great as in any other possible method of 
treatment (C II, 6); this is true in steamers of the household type as 
well as in those of institutional type, as those who may have seen the 
yellow water under steaming squash or pumpkin can testify. 

7. It is obvious that extraction of soluble constituents will depend 
largely upon length of the period of cooking (e.g., P III, 4 and 5, C I, 
4 and 5), and upon relative proportions of water and vegetable (e.g., 
compare P II, and P III, with P IV), especially as the cooking process 
nears its end and the water boils away more or less rapidly according 
to the rate at which heat is applied; e.g., compare C I, 1 with C I, 6 
(differing amounts of water at close). These two factors are widely 
variable and exceedingly uncertain, in ordinary household practice, as 
is also the relative surface exposed, when the vegetable is cut or pared. 
Add to this the varying degree of extraction possible with different 
vegetables, owing to the different proportions of readily soluble carbo- 
hydrate and salts which they contain, and it will be seen that there is 
no possible universal factor which can be applied, in dietary calculations, 
to show losses of fuel or other values of foods, incurred in cooking; or 
none which can lay claim to the sHghtest approximation to accuracy 
upon all occasions. 

Such statements as, "Boiling extracts three-fourths of the iron in 
spinach," or "one-fourth of the salts of potato" or "two-thirds of the 
sugar of carrots" may fit one instance precisely and yet be far from the 
truth in another. 

Naturally these generalizations do not apply to the "conservation" 
methods of cooking (steaming, baking, boiling in jackets, utilization of 
vegetable stocks as soups or sauces) where the loss is reduced to practi- 
cally nothing at all. One of the best of these economical methods is 
that in which the edible portion of the vegetable is cut fine and cooked 



1919] CHANGES IN FOOD VALUE OF VEGETABLES 



33 



in a small amount of water or milk which is almost entirely absorbed, and 
which consequently is served with the vegetable. This cooking may 
be done directly over the flame, or on a hot plate of asbestos or heavy 
metal, or on the back of the range, or in a double boiler. The hard, 
sweet core of young cabbage heads, heated 15 to 30 minutes in this 
fashion, is a very different product from that which has been long 
boiled in water. The same thing is true of the outer stalks at the base 
of a head of cauliflower, which, though often discarded as refuse, ap- 
parently may have a higher food value than the fleshy part, and one as 
easily extracted as that of the fleshy floweret which is usually eaten. 
(See Caul. I, 1 and 4.) 

It is also evident that preliminary soaking in cold water, or starting 
the cooking process in cold instead of in boiHng water, will greatly in- 
crease cooking losses by prolonging the period of cooking, and by adding 
the extractive power of the water at lower temperatures to that at 
boiling temperature. (C I, 4 and 5; O I, 2 and 4.) 

8. When steamed, all vegetables lose weight, mostly because of 
evaporation of water. (C III, 3; C IV, 5 and 6; S. B. II, 4; Caul. I, 
3 and 6; Cab. I, 2; Spin. I, 2 and II, 3.) When boiled in an open dish in 
excess of water, a starchy, or dry, or wilted vegetable, or one with air 
spaces which can become waterlogged, or one unusually high in crystal- 
loids (salts and sugars, which increase osmotic powers of the tissues), 
will take up water enough to gain in weight, even though it may have 
lost considerable amounts of solid matter (Pars. Ill, Car. II, green 
peas, string beans, Brussels sprouts). But a juicy or watery vegetable, 
or one protected by impermeable cuticle, loses water as well as solids, 
even when boiled in water, due no doubt to disturbances of colloidal 
systems within the tissues by the application of heat. The ease with 
which juice flows from heated meat or fruit (or from heated proto- 
plasmic structures seen under the microscope) is a matter of com- 
mon observation, as is the dryness of boiled meat in comparison with 
properly roasted meat. Again, a sound potato, boiled in its unpierced 
jacket, almost always loses a little in weight; and often a slight ac- 
cumulation of water may be perceived underneath the skin, before it 
has succeeded in escaping. Vegetables cooked in salted water (see 
Peas, Turnips, Cauliflower, Cabbage) tend to lose weight more strongly 
than do those cooked in distilled or tap water; the strong solution out- 
side the tissues draws water out of them by osmosis, as does salt on meat, 
or sugar on berries. Soaking vegetables in cold distilled or tap water, 



34 THE JOURNAL OF HOME ECONOMICS [April 

however, swells them but does not cause heavy loss of soHds (Onions 
I, 2), since the protoplasm is not killed and is able to retain its solutes to 
considerable degree for a time, at least before bacterial action shall 
have made itself felt. 

It is evident, then, that a comparison of weights before and after 
cooking can give no information as to the extent of loss of solids. Yet 
we sometimes hear the commercial canners using this line of argument, 
in denying that losses take place in blanching. But the circumstance 
that young peas may show no increase in weight during blanching, does 
not prove nor indicate that no loss of salts, sugar, or protein of the 
pea, takes place. 

9. It may be readily observed in case of a well-packed jar that the 
processing method used in home canning of vegetables or fruit sub- 
merged in a boiling water bath results in the presence of a mini- 
mum amount of juice in the jar. In Cab. II, 2 and 3, the combined 
weight of vegetables and brine or juice is less than the original weight 
of raw vegetable. In S. B. II, 5, there is an excess of water, due partly 
to the fact that there were not enough beans on hand to fill the jar, but 
also to the different method of canning, that of cooking with pressure 
steam while the jar is completely sealed, thus preventing any escape 
of liquid.) 

This small amount of juice is a very different condition from that 
which sometimes has obtained in commercially canned goods. While 
due chiefly to differences in closeness of pack, it is also due to the fact 
that during the two or three hours of processing in boiUng water bath 
the contents of the partially sealed jar are continually giving off steam 
to the water bath (even when the bath completely submerges jar and 
cover), or to the atmosphere above it, in case submersion is incomplete. 
The constantly escaping stream of air and steam bubbles, over or under 
the rubber gasket, can readily be observed during the entire period of 
processing. When the jar is lifted out of the bath, presumably the 
operator at once makes the seal tight; and, even though the seal should 
perhaps not chance to continue absolutely tight during the process of 
cooling, there is more or less vacuum remaining until the jar is opened, 
in a successful product which "keeps" well. The smaller amount of 
water or juice in the jar, then, may have only a moderate or even a rela- 
tively low extractive value, in spite of the long boihng period. Further- 
more, the flavor of this juice is good, and it can be served with the vege- 
table, which is often not the case with jars or cans containing a large 
amount of watery juice in metal containers. 



1919] CHANGES IN FOOD VALUE OF VEGETABLES 35 

We may conclude, then, that the methods for home canning, as prac- 
ticed in following the directions issued by extension workers in agri- 
culture and home economics, U. S. Dept. of Agriculture, compare very 
favorably with other methods of canning as to effect upon nutritive 
value of product, provided pains he taken to reduce losses from the 
blanching process. This precaution is particularly important in case of 
young tender peas, carrots, corn, vegetables of the cabbage and onion 
families, and any vegetables pared and cut or broken into shreds or 
short lengths before blanching. 

It is clearly of the greatest importance (as has been so often dem- 
onstrated) that the juice of vegetables escaping into cooking water 
should be conserved, and methods of making this juice palatable de- 
serve the cook's attention. If onions must be boiled in excess of water 
to reduce their flavor, at least this water may be concentrated by boil- 
ing until it can furnish a suitable flavor for milk or cream soups, or broths 
or sauces, for vegetable or meat hash or stew, or loaf or croquettes. 

A great deal of trouble has been taken to discover the best method 
of cooking each cut and kind of meat so as to secure optimum results. 
It is time that vegetable cookery received a larger share of attention from 
the average woman. The problems which arise in the cooking of each 
kind of vegetable should be given attention on their own merits. General 
directions for the cooking of the different classes as underground tubers 
and root stocks, green vegetables, etc., are exceedingly useful, yet 
further details appropriate to each occasion should not be forgotten. 
Here is one small illustration concerning a point too often overlooked: 
When some parts of a vegetable are very much tougher and more re- 
sistant than others the two should not as a rule be cooked together 
until the toughest part is "done," for this is likely to destroy the more 
delicate flavor of the tender parts. We do not expect to cook the ten- 
derloin strip and the tail piece of a porterhouse steak successfully by the 
same process; or if this is done, the tougher pieces are finely chopped 
before cooking, and this reduces the extra time needed. Often the same 
method of procedure can be used with vegetables. It is a clear waste, 
in time of high prices, to throw away the leaf petioles of kohlrabi or 
cauliflower, the centra) core of young cabbage or parsnips; very Ukely 
these have as high a soluble carbohydrate value as does the remainder of 
the vegetable. If grinding or chopping be substituted for a portion of the 
cooking process, or if these more resistant parts can be given a separate 
long slow cooking in fireless cooker or double boiler, then the palata- 



36 THE JOURNAL OF HOME ECONOMICS [April 

bility of the combination may be greatly enhanced, and its nutrients 
conserved. 

One word remains to be said, from the standpoint of modem theories 
of nutrition. Indications are not lacking that we may at last come to 
believe that spring "rheumatism" and pallor and skin disturbance; those 
cases of pyorrhea which are akin to what has sometimes been called 
scurvy, low resistance to many winter infections, and that common evil, 
constipation, can conceivably be favorably affected by such an increase 
in the diet of these vegetable salts, acids (and possibly " vitamines") , as 
occurs when we change from a winter diet of canned and heavily extracted 
vegetables to a spring diet of fresh or lightly cooked ones." At least it 
seems worthwhile to take measures to prevent our foods from being de- 
pleted of these vegetable extracts which should no more be thrown 
away than should the drippings of fat and juice which cook out of 
meat. Yet many a woman, who would be shocked at the idea of 
throwing away a meat broth, does not hesitate to discard a much more 
highly nutritious vegetable broth. 

Since the above words were written a study has appeared (Jour. 
Amer. Med. Assn., March 30, 1918) which exactly illustrates the point 
in view. Dr. Hess, a notable authority on scurvy, rickets, and other 
phases of pediatrics, considers it likely that the rickets, so commonly 
occurring among negroes in New York City, may have some relation to 
the lack of fresh vegetables and fruits in the diet. He finds that these 
emigrants from the West Indies never have the disease while living 
where the diet contains large amounts of fresh vegetables and fruits. 

SUMMARY 

1. Boiled vegetables may lose as low as 15 per cent or as high as 60 
per cent of their fuel value, according to the method of manipulation. 
(Those vegetables which are cooked within their own heavy, intact 
jackets, such as unpeeled Irish potatoes and beets, will of course lose 
much less even than this minimum.) The extent of the loss depends 
upon the amount of soluble carbohydrate and protein present in the 
vegetable tissues, as well as upon the manipulation. 

2. Losses in salts and nitrogen often, if not always, sHghtly exceed the 
fuel or caloric losses. 

2' It is of great interest and pleasure to the first holder of the Ellen H. Richards Fellow- 
ship, at the University of Chicago, who writes these lines, to learn that this doctrine was vig- 
orously propagated by that wise and far-seeing woman. 



1919] CHANGES IN FOOD VALUE OF VEGETABLES 37 

3. Blanching for 5 or 6 minutes causes losses of 8 to 15 per cent (salts, 
fuel value). Peeled and sliced vegetables lose twice as much. 

4. Salting the water (1.5 per cent solution, or about 1 tablespoon to 
the quart) decreases the losses in fuel value due to boiling. 

5. Cutting the vegetable crosswise instead of lengthwise, or into small 
instead of large pieces, increases the losses. 

6. Steaming usually cuts the caloric losses down almost to zero; also 
the salt losses, except in case of leafy tissues which expose a very large 
amount of surface to the action of the condensing vapor (cabbage, 
spinach) . However, if conditions within the steamer are such that water 
washes down over the vegetable mass, steaming may cause very large 
losses. Particularly is this the case with pressure steamers. 

7. The two factors most potent in causing variations in cooking losses 
are varying lengths of time of cooking, and varying amounts of water 
used in proportion to mass of vegetables to be cooked. 

8. Steamed vegetables always lose in weight. Boiled vegetables may 
gain in weight because their intercellular spaces take up water at the 
same time that they are losing heavily in mineral salts and soluble 
carbohydrates and proteins. 

9. Home canning often results in a maximum amount of vegetables 
and a minimum amount of watery juice in the jar, partly because of 
close packing and partly because Hquid is driven off during the period of 
processing v>'ith seal only partially made. This relatively small amount 
of juice in the jar is a great advantage from the standpoint of true 
nutritive economy, — whatever may be its effect upon ease of steriHzation 
of the vegetable mass. 



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